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Tuesday, May 07, 2013

Weekly Propagation Forecast Bulletins

Product: Weekly Highlights and Forecasts

:Issued: 2013 May 06 0122 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC web contact www.swpc.noaa.gov/weekly.html
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# Weekly Highlights and Forecasts
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Highlights of Solar and Geomagnetic Activity 29 April - 05 May 2013
Solar activity reached high levels this week when Region 1739 (N13, L=75, class/area=Dac/150 on 03 May) appeared on the east limb and unleashed an M5/Sf flare on 03 May at 1732Z. The flare was accompaned by Type II (1297 km/s) and Type IV radio emissions. A coronal mass ejection (CME) was subsequently observed in LASCO/C2 coronagraph imagery at 03/1748Z and also in STEREO-A and B COR2 imagery. Region 1739 was also responsible for an M1/Sf flare at 05/1756Z. The most prolific active region of the week was, by far, Region 1731 (N09, L=187, class/area=Dkc/420 on 28 Apr) with 17 C-class and two M-class flares to its credit. By 30 Apr, Region 1731 had developed beta-gamma-delta magnetic characteristics which it maintained through 03 May. During this period it produced an M1/1n flare at 02/0510Z and a long duration M1/2n flare at 03/1655Z. The 02 May event was associated with a tenflare (159 sfu), a Type II emission (703 km/s), and a CME first seen in LASCO/C2 imagery at 02/0524Z. The majority of the ejecta was directed north of the ecliptic, but output from the WSA-Enlil model suggested a possible scrape from the CME on 06 May. The 03 May event was not associated with a CME.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit was at high levels on 29-30 Apr and 03-04 May.
Geomagnetic field activity reached unsettled to active levels beginning late on 30 Apr and lasting through 02 May. This activity was in response to the presence of a recurrent negative polarity coronal hole high speed stream. On 01 May, activity reached major storm levels at high latitudes. Activity returned to quiet levels early on 02 May. Conditions were quiet, with the exception of one unsettled period during the latter half of 05 May with the arrival of a corotating interaction region in advance of a positive polarity recurrent coronal hole high speed stream.
Forecast of Solar and Geomagnetic Activity 06 May - 01 June 2013
Solar activity is expected to be at low levels with a chance for an isolated moderate or greater event for the extent of the outlook period.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to be high on 8-10 May and again on 24-31 May in response to recurrent coronal hole high speed streams.
Geomagnetic field activity is expected to be quiet to unsettled for the majority of the outlook period. Active levels are possible on 21-23 May in response to a recurrent coronal hole high speed stream.